1. Field of the Invention
The present invention relates to a television lens apparatus for use with a broadcast television camera and the like.
2. Description Related to the Prior Art
A broadcast television camera includes a camera tube, imaging plate or the like, and used for an indoor imaging in a studio and the like, and outdoor imaging for sport broadcasting and the like. A television lens apparatus in a quadrilateral box shape is attached to the broadcast television camera removably (see U.S. Pat. No. 7,859,592 corresponding to Japanese Patent Laid-open Publication No. 2008-124913).
Operable devices, such as a focus demand device and a zoom demand device, are connected to the television lens apparatus by a cable or the like. According to the command from the operable devices, focus adjustment and magnification adjustment of the television lens apparatus are carried out. Also, various types of electronic circuits are provided in the television lens apparatus for iris control or the like in addition to the focus adjustment and magnification adjustment.
Assuming that all of the electronic circuits in the television lens apparatus are constituted by a single circuit board, the circuit board is difficult to contain in a housing of the television lens apparatus because of a large size. Also, the maintainability of the electronic circuits is poor, as all the electronic circuits must be exchanged assuming that only one portion of the electronic circuits is broken.
In the television lens apparatus, therefore, circuit boards are constituted by each of function modules such as a control circuit board for the focus adjustment and a control circuit board for the magnification adjustment, to constitute one electronic circuit by internal wiring of the circuit boards. In such a modular structure, disposition of the circuit boards in the housing is facilitated as the size reduction of the circuit boards is possible. Its maintainability can be higher as only one of the circuit boards being broken should be exchanged.
As described in U.S. Pat. No. 7,859,592, the housing of the television lens apparatus is in a box shape (prismatic tube), and fully covers an outer surface of the lens barrel. Each of the circuit boards is attached to a lateral surface of the lens barrel to be contained in a space between the lens barrel and the housing. Assuming that the circuit boards are broken, the lens barrel must be removed from the housing together with the circuit boards, so that handlability has not been always good. Manipulation for wiring has been very laborious as the circuit boards are interconnected with a cable or the like after attaching the circuit boards to the lateral surface of the lens barrel.